code: def forward(self, x, edge_index):
      x = self.conv1(x, edge_index).relu()
      x = self.conv2(x, edge_index).relu()
      return self.lin(x)
  
imports: import os.path
  import torch
  import torch.nn.functional
  import tqdm
  from sklearn.metrics import roc_auc_score
  from torch.nn import Embedding, Linear
  import torch_geometric.transforms
  from torch_geometric.datasets import Taobao
  from torch_geometric.loader import LinkNeighborLoader
  from torch_geometric.nn import SAGEConv
  from torch_geometric.utils.convert import to_scipy_sparse_matrix
label_desc: Use image node_id 2 for calling the ItemGNNEncoder obj's underlying member method code with example usage: obj.forward(x, edge_index) and returns: self